End effector inspection apparatus and method

ABSTRACT

An end effector for inspecting a structure is provided. An end effector includes a magnetically coupled attachment member for connecting the end effector to a control system bridge. An end effector also includes a telescoping arm at least partially disposed inside a tube. A force mechanism provides a force to extend the arm from the tube. A probe attachment, connected to the end of the arm opposite the tube, provides motion in at least one axis relative to the arm for an inspection probe attached to the end effector. Cut-off switches can be used to alert a control system to a separation of the end effector from the bridge and proximity of the bridge to a structure under inspection.

CROSS-REFERENCE TO RELATED APPLICATIONS

The contents of co-pending applications filed concurrently herewith andentitled “Magnetically Attracted Inspecting Apparatus and Method Using aFluid Bearing,” “Magnetically Attracted Inspecting Apparatus and MethodUsing a Ball Bearing,” “Alignment Compensator for Magnetically AttractedInspecting Apparatus and Method,” and “Apparatus and Method for AreaLimited-Access Through Transmission Ultrasonic Inspection” areincorporated by reference in their entireties. The contents of U.S. Pat.No. 6,722,202 to Kennedy are incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to an apparatus and method forinspecting a structure and, more particularly, to an apparatus andmethod for connecting an inspection probe to a control system.

BACKGROUND

Structures are commonly inspected for any type of internal or externaldamage to or flaws in the structure. For example, inspection may berequired to validate the integrity and fitness of a structure forcontinued use in manufacturing and future ongoing use in-service. Atypical inspection method is non-destructive inspection (NDI) whichinvolves thoroughly examining a structure without harming the structureor requiring significant disassembly of a product including thestructure. Among the structures that are routinely tested are compositestructures, such as composite sandwich structures and other adhesivebonded panels and assemblies. In this regard, composite structures arecommonly used throughout the aircraft industry because of theengineering qualities, design flexibility and low weight of compositestructures, such as the stiffness-to-weight ratio of a compositesandwich structure. For example, composite structures are used tofabricate parts for F-22 aircraft. As such, it is frequently desirableto inspect composite structures to identify any flaws, such as cracks,voids or porosity, which could adversely affect the performance of thecomposite structure. For example, typical flaws in composite sandwichstructures, generally made of one or more layers of lightweighthoneycomb or foam core material with composite or metal skins bonded toeach side of the core, include disbonds which occur at the interfacesbetween the core and the skin or between the core and a septumintermediate skin.

Non-destructive inspection may be performed using a variety of methods,including pulse-echo (PE), through transmission (TT), or shear waveinspection techniques to obtain data, such as for thickness gauging,detection of laminar defects and porosity, and/or crack detection in thestructure. Resonance, pulse echo or mechanical impedance sensors may beused to provide indications of voids or porosity, such as in adhesivebondlines of the structure. High resolution inspection of aircraftstructure are commonly performed using semi-automated ultrasonic testing(UT) to provide a plan view image of the part or structure underinspection. While solid laminates may be inspected using one-sided pulseecho ultrasonic (PEU) testing, composite sandwich structures typicallyrequire through-transmission ultrasonic (TTU) testing for highresolution inspection. In through-transmission ultrasonic inspection,ultrasonic sensors such as transducers, or a transducer and a receiversensor, are positioned facing the other but contacting opposite sides ofthe structure to be inspected such as opposite surfaces of a compositematerial. An ultrasonic signal is transmitted by at least one of thetransducers, propagated through the structure, and received by the othertransducer. Data acquired by sensors, such as TTU transducers, istypically processed by a processing element, and the processed data maybe presented to a user via a display.

Non-destructive inspection may be performed manually by technicians whotypically move an appropriate sensor over the structure. Manual scanninggenerally consists of a trained technician holding a sensor and movingthe sensor along the structure to ensure the sensor is capable oftesting all desired portions of the structure. In many situations, thetechnician must repeatedly move the sensor side-to-side in one directionwhile simultaneously indexing the sensor in another direction. For atechnician standing beside a structure, the technician may repeatedlymove the sensor right and left, and back again, while indexing thesensor between each pass. In addition, because the sensors typically donot associate location information with the acquired data, the sametechnician who is manually scanning the structure must also watch thesensor display while scanning the structure to determine where thedefects, if any, are located in the structure. The quality of theinspection, therefore, depends in large part upon the technician'sperformance, not only regarding the motion of the sensor, but also theattentiveness of the technician in interpreting the displayed data.Thus, manual scanning of structures is time-consuming, labor-intensive,and prone to human error.

Semi-automated inspection systems have been developed to overcome someof the shortcomings with manual inspection techniques. For example, theMobile Automated Scanner (MAUS®) system is a mobile scanning system thatgenerally employs a fixed frame and one or more automated scanning headstypically adapted for ultrasonic inspection. A MAUS system, such as aMAUS-V system, may be used with pulse-echo, shear wave, andthrough-transmission sensors. The fixed frame may be attached to asurface of a structure to be inspected by vacuum suction cups, magnets,or like affixation methods. Smaller MAUS systems may be portable unitsmanually moved over the surface of a structure by a technician. However,for through-transmission ultrasonic inspection, a semi-automatedinspection system requires access to both sides or surfaces of astructure which, at least in some circumstances, will be problematic, ifnot impossible, particularly for semi-automated systems that use a fixedframe for control of automated scan heads.

Automated inspection systems have also been developed to overcome themyriad of shortcomings with manual inspection techniques. For example,the Automated Ultrasonic Scanning System (AUSS®)) system is a complexmechanical scanning system that employs through-transmission ultrasonicinspection. The AUSS system can also perform pulse echo inspections, andsimultaneous dual frequency inspections. The AUSS system has roboticallycontrolled probe arms that must be positioned proximate the opposedsurfaces of the structure undergoing inspection with one probe armmoving an ultrasonic transmitter along one surface of the structure, andthe other probe arm correspondingly moving an ultrasonic receiver alongthe opposed surface of the structure. To maintain the ultrasonictransmitter and receiver in proper alignment and spacing with oneanother and with the structure undergoing inspection, the AUSS-X systemhas a complex positioning system that provides motion control in tenaxes.

One difficulty when using control systems is the connection between thecontrol system and the inspection probe. Typically, control arms anddirect attachments are used to connect a probe to a control system.Unfortunately, however, using a control arm or directly attaching acontrol system to a probe brings the control system into proximity withthe structure under inspection. The proximity of the control system tothe structure can lead to damage to the control system and the part suchas instances where the control system impacts the structure.

Accordingly, a need exists for an improved non-destructive inspectiondevice and method to inspect a structure.

SUMMARY OF THE INVENTION

An end effector inspection apparatus and method are provided accordingto various embodiments of the present invention. An end effector is usedto connect a control system to an inspection probe. An end effector alsoprovides separation between the control system and the inspection probeto decrease the chance of damage to either the control system or thestructure. An end effector may be used for manual, semi-automated, andautomated inspection of a structure, but is especially useful forconnecting an inspection probe to a semi-automated or automated controlsystem. An end effector may also provide such features as safety cut-offswitches, magnet release clamps, alignment members and alignmentindentations for orientation and alignment for attachment, clamping tubemounts, a detachable extension tube, and a retracted locking positionand such functions as quick release from a control system to preventdamage.

An end effector according to one embodiment of the present inventionincludes a telescoping arm, a tube, a force mechanism, and amagnetically coupled attachment member. The telescoping arm is at leastpartially disposed within the tube. The force mechanism is coupled tothe arm and the tube to exert a force to extend the arm from the tube.The magnetically coupled attachment member connects to the tube and mayinclude at least one releasable clamp for connecting to the tube. Thereleasable clamp may allow for positioning of the tube with respect tothe attachment member, such as to slide the tube in one directionrelative to the attachment member. A detachable extension tube may beattached to the primary tube for increasing the length of thetelescoping arm relative to the position of the attachment member. Theattachment member may include a cut-off switch to indicate when theattachment member is not connected to a support mechanism such as acontrol system bridge. The attachment member may include alignmentmembers which are used when attaching the attachment member to a supportmechanism such as a control system bridge. The attachment member mayalso include a magnetic coupling offset release clamp for releasing themagnetic attraction between the attachment member and a supportmechanism such as for attaching or disengaging the attachment memberfrom the support mechanism.

The arm or the tube may include a cut-off switch to indicate when thearm is retracted into the tube beyond the predefined amount ofretraction. Typically, the arm is rotatably fixed with respect to thetube such that the arm does not rotate within the tube. Correspondinggrooves and ridges in and on the arm and tube may prevent rotation ofthe arm within the tube. An indentation or dent around a portion of thearm or within a portion of the tube and a corresponding bump inside thetube or around the arm may fix the arm within the tube in a retractedposition where the bump extends into the tube. A bump may include atleast one depressible ball which may extend into the dent. The cut-offswitch on the arm or tube may indicate when the arm is retracted intothe tube beyond the interface of the dent and the bump.

A force mechanism between a tube and an arm may be, for example, aretractable metal spring, a compressible spring, or a piston. Bearingsmay be included to support the arm in the tube. The arm rides on thebearings within the tube in order to extend from and retract into thetube. A probe attachment may be coupled to the distal end of the armfrom the tube and provide at least one axis of motion relative to thearm. A second-axis rotor may be connected between the tube andattachment member in order to provide at least one additional axis ofrotation for the tube relative to the attachment member.

According to another aspect of the present invention, an apparatus forinspecting a structure includes an end effector with a telescoping arm,a tube, a magnetically coupled attachment member, and an inspectionprobe connected to the distal end of the arm from the tube. Theapparatus for inspecting a structure may also include a control systemcomprising a bridge magnetically coupled to the attachment member of theend effector. The attachment member may include alignment membersinserted into corresponding indentations in the bridge. The alignmentmembers in the corresponding indentations are used for positioning theattachment member with respect to the bridge for magnetic coupling. Theattachment member may include a magnetic coupling offset release clampfor releasing the magnetic attraction or preventing the full magneticattraction of the coupling between the attachment member and the bridge.For example, the magnetic coupling offset release clamp may include anextension which protrudes from the attachment member between theattachment member and the bridge for providing separation between thebridge and the attachment member. The bridge or the attachment membermay include a cut-off switch for indicating when the bridge and theattachment member are connected and/or separated. The end effector mayalso include a probe attachment coupled to the distal end of the armfrom the tube for connecting the end effector to the inspection probe.

According to yet another aspect of the present invention, a method ofinspecting a structure is provided. The method includes the steps ofmagnetically coupling a control system to an attachment member of an endeffector, coupling an inspection probe to the end effector, positioningan inspection probe against the surface of a structure, and controllinginspection of the structure with the control system. The step ofpositioning the inspection probe may include the step of telescoping anarm of the end effector to permit the inspection probe to contact thesurface of the structure. The step of telescoping the arm of the endeffector may include the step of exerting a force upon the arm of theend effector to extend the arm from the tube. The method may alsoinclude the step of releasing the magnetic coupling of the bridge andthe attachment member by separating the bridge and the attachmentmember. The separation of the bridge and the attachment member may beperformed by protruding an extension from at least one of the bridge andthe attachment member between the bridge and the attachment member.

These and other characteristics, as well as additional details, of thepresent invention are further described in the Detailed Description withreference to these and other embodiments.

BRIEF DESCRIPTION OF THE DRAWING(S)

Having thus described the invention in general terms, reference will nowbe made to the accompanying drawings, which are not necessarily drawn toscale, and wherein:

FIG. 1 is a side perspective view of an end effector connecting acontrol bridge to an inspection probe according to an embodiment of thepresent invention;

FIG. 1A is a schematic diagram of a retractable metal spring forcemechanism for an end effector according to an embodiment of the presentinvention;

FIG. 1B is a schematic diagram of a piston force mechanism for an endeffector according to an embodiment of the present invention;

FIG. 1C is a schematic diagram of a compressible spring force mechanismfor an end effector according to an embodiment of the present invention;

FIG. 2 is a bottom perspective view of the end effector connecting acontrol bridge to an inspection probe according to an embodiment of thepresent invention;

FIG. 3 is a side perspective view of a connection between an endeffector and a control bridge according to an embodiment of the presentinvention;

FIG. 4 is an orthogonal side perspective view of the connection betweenthe end effector and the control bridge;

FIG. 4A is a schematic diagram of alignment members and bridge baseindentations according to an embodiment of the present invention;

FIG. 5 is a side view of the connection between the end effector and thecontrol bridge;

FIG. 6 is a side perspective view of an end effector with a tubeextension connecting a control bridge to an inspection probe accordingto an embodiment of the present invention;

FIG. 7 is an overhead perspective view of an end effector of the presentinvention being used to scan a structure; and

FIG. 8 is a side view of the end effector being used to scan thestructure.

DETAILED DESCRIPTION

The present invention will be described more fully with reference to theaccompanying drawings. Some, but not all, embodiments of the inventionare shown. The invention may be embodied in many different forms andshould not be construed as limited to the embodiments described. Likenumbers and variables refer to like elements and parameters throughoutthe drawings.

An end effector of the present invention can be used to connect acontrol system, such as a control bridge of an AUSS-X to an inspectionprobe. An end effector may advantageously be used with magneticallycoupled inspection probes which do not require multi-axis roboticsystems. Rather, magnetically coupled inspection probes only require oneof the probes to be driven over a surface of the structure underinspection. An end effector operably engages the inspection probe andtranslates a force from the control system for moving the probe across asurface of a structure. At the same time, an end effector permits theprobe to rotate and extend to follow the contour of the surface of thestructure. For example, an end effector may be connected to the probeusing a rotatable knuckle attachment which provides for on-axisrotation; off-axis rotation, also referred to as bending or hinging; andlinear extension of the probe to permit the probe to follow the contourof the surface of the structure in any direction of movement over thesurface while maintaining magnetic coupling with a probe on an opposingsurface of the structure. An end effector is used to permit aninspection probe to contact, and maintain contact with, the structure.Accordingly, an end effector permits contour-following for magneticallycoupled scanning of large, contoured structures. For example, an endeffector may be used for non-destructive PE and TTU inspection of acomposite payload fairing such as for low frequency ultrasonic bondinspection and eddy current testing.

FIG. 1 is a side perspective view of an end effector connecting acontrol bridge to an inspection probe according to an embodiment of thepresent invention. FIG. 2 is a bottom perspective view of the endeffector. Typically, an end effector is used to attach an inspectionprobe 14 to the base 102 of a bridge 100 of a control system. The bridge100 of the control system is used to control an inspection probe 14,such as moving the probe 14 back and forth over a structure underinspection. An end effector includes a telescoping arm 4 inside a tube 2such as a larger hollow sleeve. For example, the arm 4 may slide oninternal bearings inside the hollow tube 2 to permit extension andretraction of the arm 4, such as the ball and socket bearings 294 shownin FIG. 1C. The arm 4 may freely extend and retract in order to permitthe magnetically coupled inspection probe 14 to contact the structureunder inspection and follow contours of a surface of the structurewithout requiring the control system bridge 100 to be preciselyprogrammed for the contours of the surface of the structure. Forexample, the bridge 100 of a control system using an end effector with atwo foot telescoping arm 4 would only need to keep within approximatelytwo feet of proximity of the structure. The telescoping arm 4 and themulti-axis rotation of the magnetically coupled inspection probe 14provide the difference between the rough positioning of the controlsystem bridge 100 and the contours of the surface of the structure.Typically an arm and a tube are cylindrical with circularcross-sectional circumferences. However, an arm and a tube may be formedwith corresponding non-circular cross-sectional shapes, such as anellipse or hexagon cross-sectional shape. Additional corresponding,non-circular cross-sectional shapes for an arm and a tube include, forexample, regular polygons, including triangles, squares, rectangles,octagons, and the like and irregular polygons, shapes, configurations,and combinations.

An end effector typically includes a force mechanism to provide aconstant outward force to extend the arm 4. An outward force helps toensure that the end effector does not unintentionally pull theinspection probe 14 off the structure under inspection, but insteadhelps to keep the inspection probe 14 against the structure. A forcemechanism is preferably adapted to provide a constant outward forcewhile permitting the telescoping arm 4 to easily retract into the hollowtube 2.

An end effector of the present invention may be used for manual,semi-automated, and automated inspection of a structure, but isespecially useful for connecting an inspection probe to a semi-automatedor automated control system. An example of a semi-automated controlsystem which can be used with an embodiment of the present invention isa robotic gantry scanning system manufactured by CIMCORP PrecisionsSystems, Inc., of Ulvila, Finland, a part of which is now PAR Systems,Inc., of Shoreview, Minn., with a CIMROC®2 controller and an XR6050bridge manufactured by GCA, Inc., and using ScanMaster™ control softwareby ScanMaster Systems (IRT) Ltd. (formerly IRT) of Hod Ha'Sharon,Israel, and IRT ScanMaster Systems, Inc., of Nashua, N.H.

The end effector is attached to the base 102 of the bridge 100 of thecontrol system with an attachment member 40. Magnetic coupling is usedto attach the end effector to the control system. For example, magnets20 on the attachment member 40 may be magnetically attracted to thebridge base 102 constructed of stainless steel or other ferromagneticmaterial. Various other magnetic coupling mechanisms may be used. Forexample, the magnets and the ferromagnetic elements may be interchanged.Two magnets may be used. “Magnet” includes permanent magnets andelectromagnets. To assist in attachment of the end effector to thecontrol system, an attachment member 40 may include offset releaseclamps 34 that are used to provide a separation to decouple the endeffector from the control system, such as decreasing the magneticattraction of the magnets 20 of the attachment member 40 to the bridgebase 102 by separating the magnets 20 from the bridge base 102.

The magnetic coupling allows the end effector to safely break away fromthe control system, such as if the end effector or probe collides with aportion of the structure under inspection. The magnetic coupling mayalso permit the end effector to rotate with respect to the controlsystem bridge 100 in the case of a collision, such as where the magneticcoupling is strong enough to keep the end effector and the controlsystem attached but where alignment members 50 of the attachment member40 of the end effector are disengaged from corresponding indentations52, 53 in the control system bridge 100. By comparison to currentsystems which do not separate or may break apart such as using plasticscrews to permit separation of an inspection probe from a controlbridge, magnetic coupling may be quickly and easily reattached and iseasily adjusted such as using different magnets to control the strengthof a force that can separate an end effector from a control bridge.Accordingly, in accordance with embodiments of the present invention,the magnetic coupling between an end effector and a control system is aforce strong enough to retain the end effector in a fixed positionrelative to the control system but weak enough to permit the endeffector to break away from or rotate with respect to the control systemdue to a sufficient amount of force directed against the end effector,such as a predetermined force perpendicular to the motion of the endeffector. Similarly, in accordance with embodiments of the presentinvention, the force of the magnetic coupling should be weak enough topermit manual separation of the end effector from the control system,such as using offset release clamps 34.

A probe attachment 18 may be affixed to the end of the arm 4 oppositethe tube 2 in order to hold an inspection probe 14. A probe attachment18 may provide for multi-axis rotation of the inspection probe 14 withrespect to the arm 4 and thereby the end effector and control system.For example, a probe attachment 18 may be a yoke attachment affixed toopposing sides of an inspection probe 14 with rotatable hinges attachedto the inspection probe 14 and a rotatable and/or hinged attachment tothe arm 4.

An end effector may include additional features such as quick releaseclamps 30 which are used to position a tube 2 of the end effector withrespect to the attachment member 40. Quick release clamps 30 may be usedto conveniently increase or decrease the reach of the control systemusing the end effector to position an inspection probe 14 against astructure under inspection. The quick release clamps 30 hold the magnets20 off the bridge base 102 to allow easy attachment and detachment ofthe end effector to and from the control system bridge 100. An examplequick release clamp is a clamp which permits manual releasing andsecuring of the clamp, such as and/or similar to bicycle quick releaseskewers that use levered cams to exert a clamping force on a skewer. Anend effector may also include offset release clamps 34 that allow anoperator to align the end effector, specifically the attachment member40 of the end effector, as it is attached to a control system bridge100. Offset release clamps 34 also allow an operator to easily remove anend effector from a control system bridge 100, such as when scanning iscomplete or to perform other types of scanning. An offset release clampis a clamp which permits manual adjustment of an extension forseparating a magnetic coupling between a control system and an endeffector and/or holding apart a partial magnetic coupling duringattachment or adjustment of a control system and an end effector, suchas a levered cam which translates a rotational force to a linear force.Typically, an offset release clamp would provide at least two fixedpositions, such as an open position to separate or hold apart a controlsystem and an end effector and a closed position when a control systemand an end effector are attached.

A force mechanism is included in the end effector to provide an outwardforce to extend the arm 4 from the tube 2, such as the outward forces268, 278, 288 of FIGS. 1A, 1B, and 1C. As shown in FIG. 1A, an exampleforce mechanism may be a retractable metal spring 260 attached to theend 262 of the arm 4 inside the tube 2 and the end 264 of the tube 2through which the arm 4 extends. Another example force mechanism is acompressible spring 270 as shown in FIG. 1C. Yet another example forcemechanism is a piston 280 as shown in FIG. 1B, such as a gas piston, topress on and drive the arm 4 out of the tube 2. Other types of forcemechanisms may be used to provide an outward force for the telescopingarm 4. Preferably, the force mechanism provides a constant outward forcewhich is sufficient to extend the arm 4 and the inspection probe 14 forpositioning and holding the inspection probe 14 against a surface of thestructure under inspection.

Typically, the arm of an end effector of the present invention isrotatably fixed with respect to the tube such that the arm does notrotate within the tube to permit the control system to know and/ordetermine the orientation of a probe on the surface of a structure.Corresponding grooves and ridges in and on the arm and tube, such asflats, splines, or keys, may prevent rotation of the arm within thetube. For example, an arm may include indentations or grooves along aportion of the length of the arm which correspond to extensions orridges on the inside circumference of a tube. Alternatively, or inaddition, an arm and a tube may be formed with correspondingnon-circular shapes, such as an ellipse or hexagon cross-sectionalshapes, to prevent the arm from rotating with the tube while permittingthe arm to extend from and retract within the tube. Additionalcorresponding, non-circular cross-sectional shapes include, for example,regular polygons and irregular polygons as described further above.

An end effector may be adapted to provide a releasable latch for fixedretraction of the arm 4 within the tube 2. For example, as shown in FIG.1B, the arm 4 may include a dent 290 around at least a portion of thecircumference of the arm 4, such as proximate the distal end of the arm4 from the tube 2. The tube 2 may then include a bump 292, such asdepressible balls, which extends into the dent of the arm 4, thuscreating a releaseable latch. The ball and dent latch stop position 6would preferably hold the arm 4 in a fixed, retracted position in thetube 2 to overcome the outward force of the force mechanism such as toallow for movement of a control system bridge with an attached endeffector and inspection probe before, during, or after scanning astructure.

A cut-off switch 8 may be used to provide information as to when the arm4 may be retracted into the tube beyond a predefined location. Thecut-off switch 8 signals when it is tripped. For example, if the arm 4extends past the ball and dent latch stop position 6 within the tube,the cut-off switch 8 may be activated to indicate that the controlsystem bridge 100 is too close to the structure under inspection. Acut-off switch for an embodiment of the present invention may include adepressible switch, a radio frequency chip, an optical sensor, a linearwheel, or other mechanism to indicate a position, attachment, orseparation. For example, an attachment member 40 may include adepressible switch to indicate attachment and/or separation, and a tube2 may include an optical sensor to indicate when the arm 4 passes apredefined retracted position.

The attachment member 40 includes alignment members 50 which correspondto indentations 52, 53 in the bridge base 102 which are positioned toprovide for a predetermined orientation and alignment of the endeffector with respect to the control system bridge 100. Alignmentmembers 50 may be inverted conical extensions from the attachment member40 which fit within cylindrical indentations 52 or conical indentations53 in the bridge base 102. By using inverted conical alignment members50, the alignment members 50 may be off-set or misaligned from thecorresponding indentations in the bridge base 102 and provide for properalignment and orientation of the end effector with respect to thecontrol system bridge 100 as the alignment members 50 are pulled intothe indentations 52, 53 in the bridge base 102 by the magnetic couplingbetween the attachment member 40 and the control system bridge 100. Forexample, the magnets 20 of the attachment member 40 pulled the alignmentmembers 50 up and into the indentations of the stainless steel bridgebase 102. For example, FIG. 4A shows alignment members 50 extending intocorresponding bridge indentations 52, 53. The alignment member 50 may besized such that when the attachment member 40 is adjacent to the bridgebase 102, the bridge indentations 52, 53 hold the alignment members 50in a central position relative to the bridge indentations 52, 53.Alignment members and alignment indentations may be other geometric andstructural shapes which provide for orientation and alignment of anattachment member and a control system bridge. An extension 36 of anoffset release clamp 34 may provide for separation between the bridgebase 102 and the attachment member 40 for positioning the alignmentmembers 50 with respect to the bridge indentations 52, 53. An extension36 of an offset release clamp 34 also provides separation of the bridgebase 102 and the attachment member 40 in order to reduce the magneticattraction between the magnet 20 and the bridge base 102 to permitattachment and removal of the end effector to the control system inaddition to the orientation of the end effector with respect to thecontrol system bridge 100 for affixing the end effector to the controlsystem. Other shapes, sizes, and types of extensions from orindentations in the attachment member and corresponding indentations orextensions in the control system bridge 100 or bridge base 102 may beused to orient in position an end effector with respect to a controlsystem bridge 100 in accordance with embodiments of the presentinvention.

A cut-off switch 310 may be positioned in the center of the attachmentmember 40, or at another location, in order to provide information as towhen the attachment member 40 and the control system bridge 100 areaffixed or separated. For example, the cut-off switch 310 may bedepressed by the bridge base 102 when the end effector is magneticallycoupled to the bridge base 102 by the magnets 20 of the attachmentmember 40. When the end effector is separated from the control systembridge 100, the cut-off switch is no longer depressed and may indicatethat the end effector has separated from the control system bridge 100.For example, a cut-off switch 310 providing information that an endeffector has separated from a control system bridge 100 may indicate toturn off the power to the control system bridge 100 or, moreparticularly, to stop motion of the control system bridge 100 to preventa collision between the control system bridge 100 and the structureunder inspection, or further damage to the control system bridge 100and/or of the structure under inspection. A cut-off switch 310 may bepositioned in other areas of the attachment member 40 or on the controlsystem bridge 100 or bridge base 102 such that the cut-off switchprovides information as to when the end effector and control systembridge are affixed or detached in accordance with embodiments of thepresent invention.

An end effector can separate from the control system bridge. If a forceon the end effector overcomes the attractive force of the magneticcoupling between the attachment member 40 and the control system bridge100 or bridge base 102, the end effector will pull away or separate fromthe control system bridge 100 or bridge base 102. To prevent the endeffector from falling away from the control system bridge 100 andimpacting the structure, a loose connector 38 may be used between theend effector and the control system bridge 100, such as an elasticconnection which permits the end effector to separate from the controlsystem bridge 100 but prevents the end effector from falling to thestructure under inspection. For example, if the control system bridge isgenerally separated from a structure under inspection using an endeffector by approximately two feet, a connector 38, such as an elasticconnection, can provide for one foot of separation of the end effectorfrom the control system bridge 100. Thus, if a force such as a collisionof the end effector with the structure under inspection, causing the endeffector to separate from the control system bridge 100, the connector38 may prevent the end effector from completely falling and impactingthe structure under inspection. But by allowing the end effector toseparate from the control system bridge 100, damage or further damage tothe control system bridge 100 and/or the structure under inspection maybe prevented.

FIG. 6 is a side perspective view of an end effector with a tubeextension connecting a control bridge to an inspection probe accordingto an embodiment of the present invention. A tube extension 600 may beaffixed to the tube 2 of an end effector in order to provide additionallength of the arm 4 for positioning and holding an inspection probe 14against a surface of a structure under inspection. The tube extension600 also provides additional separation between the structure underinspection and the control system bridge 100. An extension 600 of an endeffector tube 2 may be a second tube, rod, or other cylindricalstructure having the same outer circumference shape and diameter as theend effector tube. The extension 600 may be detachable, such as bythreading the ends of the tube 2 and the extension 600 together using athreaded rod which screws into a portion of the tube 2 and the extension600. Using quick release clamps 30, the tube 2 and tube extension 600may be positioned with respect to the control system bridge 100 bysliding the tube 2 and extension 600 with respect to the attachmentmember 40. Using an end effector of the present invention, andparticularly an end effector with a tube extension 600, allows a controlsystem to inspect larger, more complex structures such as inspecting aportion of a Sea Launch payload fairing. A tube extension 600 providesan end effector the ability to extend substantial distances away from acontrol system bridge 100. End effectors of a present invention may alsodecrease the cost of inspection of a structure by using an end effectorof the present invention which permits inspection of large, complexstructures rather than requiring the use of costly multi-arm, multi-axiscontrol systems.

FIG. 7 is an overhead perspective view of an end effector of the presentinvention being used to scan a structure. FIG. 8 is a side view of theend effector being used to scan the structure. The end effector of FIGS.7 and 8 include two tube sections, a tube 2 and a second access rotortube 700, to permit increased orientation of the end effector. Thesecond tube may also provide increased extension from a control bridge100, such as where the second access rotor tube 700 also includes atelescoping arm to which the tube 2 connects. In the embodiment shown inFIGS. 7 and 8, a bridge base 102 of a control system bridge 100magnetically couples to an attachment member 40 of a second axis rotor700. The second axis rotor 700 is connected to a support mechanism 41 oftube 2. An arm 4 extends from tube 2 and attaches to an inspection probe14 using a probe attachment 18. A second-axis rotor 700 may help toprovide improved orientation for pressing and holding an inspectionprobe 14 against a structure 12 to be inspected.

An end effector according to the present invention provides forinspection of a greater variety of structures using a typical controlsystem such as a robotic gantry system. The end effector and features ofthe end effector such as quick release clamps for adjusting the positionof a tube, offset release clamps for releasing magnetic coupling of theend effector to a control bridge and tube extensions reduce set-up andchange-out times for scanning structures. Magnetic coupling of anattachment member of an end effector of the present invention providesfor breakaway capabilities. Cut-off switches on an attachment member ora control system bridge and on an arm or a tube provide emergencycut-off capabilities. A constant outward force to extend the arm fromthe tube allows for use of magnetically-coupled inspection probes bypushing and holding the magnetically coupled inspection probe againstthe surface of a part under inspection. In addition, traditionalpulse-echo UT and other one-sided inspection techniques are capable ofusing end effectors according to embodiments of the present invention.

In operation a method of inspecting a structure using an end effector ofthe present invention may be performed by magnetically coupling a bridgeof a control system to an attachment member of an end effector, couplingan inspection probe to the end effector, positioning the inspectionprobe against a surface of the structure, and controlling inspection ofthe structure with the control system. Positioning an inspection probeagainst a surface of the structure may be performed by telescoping thearm of the end effector to permit the inspection probe to contact thesurface of the structure. For example, a constant force may be exertedupon the arm of the end effector to extend the arm from the tube inorder to press an inspection probe against the surface of the structure.In operation, the magnetic coupling of the bridge and the attachmentmember may be released by separating the bridge and the attachmentmember, such as protruding an extension from an offset release clampbetween the bridge and the attachment member.

Accordingly, provided is an end effector for inspecting a structure. Anend effector includes a magnetically coupled attachment member forconnecting the end effector to a control system bridge. An end effectoralso includes a telescoping arm at least partially disposed inside atube. A force mechanism provides a force to extend the arm from thetube. A probe attachment, connected to the end of the arm opposite thetube, provides motion in at least one axis relative to the arm for aninspection probe attached to the end effector. Cut-off switches can beused to alert a control system to a separation of the end effector fromthe bridge and proximity of the bridge to a structure under inspection.

Many modifications and other embodiments of the inventions set forthwill come to mind to one skilled in the art to which these inventionspertain having the benefit of the teachings presented in the foregoingdescriptions and the associated drawings. Therefore, it is to beunderstood that the inventions are not to be limited to the specificembodiments disclosed and that modifications and other embodiments areintended to be included within the scope of the appended claims.Although specific terms are employed, they are used in a generic anddescriptive sense only and not for purposes of limitation.

1. An end effector comprising: a telescoping arm; a tube for receivingsaid telescoping arm, wherein said arm is at least partially disposedwithin said tube; a force mechanism interoperably coupled to said armand said tube for providing a force to dynamically extend said arm fromsaid tube; and an attachment member connected to said tube formagnetically attaching the end effector to another component by magneticcoupling and from which said telescoping arm extends, wherein saidattachment member comprises at least one magnetic coupling mechanismselected from the group of a magnet and ferromagnetic material, andwherein said magnetic coupling mechanism is capable of cooperating witha magnetic coupling mechanism of said another component to create themagnetic coupling between said end effector and said another component,wherein said attachment member comprises at least one alignment membercapable of providing alignment of said end effector with respect to atleast one corresponding indentation of said another component for whensaid end effector is magnetically attached to said another component. 2.The end effector of claim 1, wherein said attachment member furthercomprises at least one releasable clamp for connecting said attachmentmember to said tube.
 3. The end effector of claim 2, wherein saidreleasable clamp is capable of permitting adjustment of the position ofsaid tube with respect to said attachment member by releasing saidreleasable clamp connecting said attachment member to said tube.
 4. Theend effector of claim 1, further comprising a detachable extension tubeconnected between said tube and said attachment member, wherein saiddetachable extension tube is capable of being detached from said tubeand said attachment member and wherein said tube and said attachmentmember are capable of being connected without said detachable extensiontube.
 5. The end effector of claim 1, further comprising a cut-offswitch, connected to at least one of said arm and said tube, to indicatewhen said arm is retracted into said tube beyond a predefined amount ofretraction.
 6. The end effector of claim 1, further comprising a cut offswitch, connected to said attachment member, to indicate at least one ofwhen said attachment member is separated from the another component andwhen said attachment member is connected to the another component. 7.The end effector of claim 1, wherein said arm is rotatably fixed withrespect to said tube.
 8. The end effector of claim 7, wherein said armand said tube are formed with corresponding, non-circularcross-sectional shapes to prevent rotation, such that said arm isrotatably fixed with respect to said tube.
 9. The end effector of claim1, further comprising a releasable latch, connected to at least one ofsaid arm and said tube, for affixing said arm within said tube in aretracted position.
 10. The end effector of claim 9, further comprisinga cut-off switch, connected to at least one of said arm and said tube,to indicate when said arm is retracted in to said tube beyond saidreleasable latch.
 11. The end effector of claim 1, wherein saidattachment member comprises at least one magnetic coupling offsetrelease clamp.
 12. The end effector of claim 11, wherein said magneticcoupling offset release clamp comprises at least one extension, whereinsaid extension is adapted to adjustably protrude from said attachmentmember.
 13. The end effector of claim 1, wherein said force mechanismcomprises a retractable metal spring.
 14. The end effector of claim 1,further comprising bearings to support said arm in said tube, whereinsaid bearings are capable of permitting said arm to extend from andretract into said tube.
 15. The end effector of claim 1, furthercomprising a probe attachment coupled to the distal end of said arm fromsaid tube, wherein said probe attachment provides at least one axis ofmotion relative to said arm.
 16. The end effector of claim 1, furthercomprising a second-axis rotor connected to said tube, wherein saidattachment member connects to said second-axis rotor to connect to saidtube.
 17. An apparatus for inspection a structure comprising: an endeffector, comprising; a telescoping arm; a tube for receiving saidtelescoping arm, wherein said arm is at least partially disposed withinsaid tube; a force mechanism interoperably coupled to said arm and saidtube for providing a force to dynamically extend said arm from saidtube; and an attachment member connected to said tube for magneticallyattaching the end effector to another component by magnetic coupling andfrom which said telescoping arm extends, wherein said attachment membercomprises at least one magnetic coupling mechanism selected from thegroup of a magnet and a ferromagnetic material, and wherein saidmagnetic coupling mechanism is capable of cooperating with a magneticcoupling mechanism of said another component to create the magneticcoupling between said end effector and said another component, whereinsaid attachment member comprises at least one alignment member capableof providing alignment of said end effector with respect to at least onecorresponding indentation of said another component for when said endeffector is magnetically attached to said another component; and aninspection probe connected to the distal end of said arm from said tube,wherein said end effector is capable of applying a force to said probefor pressing said probe against a surface of the structure.
 18. Theapparatus of claim 17, further comprising a control system comprising abridge magnetically coupled to said attachment member, wherein saidcontrol system is capable of applying a force to said probe for movingsaid probe across the surface of the structure, and wherein said bridgeis said another component.
 19. The apparatus of claim 18, wherein saidattachment member comprises at least one magnetic coupling offsetrelease clamp.
 20. The apparatus of claim 19, wherein said magneticcoupling offset release clamp comprises at least one extension, whereinsaid extension is adapted to adjustably protrude from said attachmentmember between said attachment member and said bridge.
 21. The apparatusof claim 17, further comprising a cut-off switch, connected to at leastone of said another component and said attachment member, for indicatingat least one of when said another component and said attachment memberare magnetically coupled and when said another component and saidattachment member are separated.
 22. The apparatus of claim 17, whereinsaid end effector further comprises a probe attachment coupled to thedistal end of said arm from said tube for connecting said inspectionprobe to said arm, wherein said probe attachment provides at least oneaxis of motion for said inspection probe relative to said arm.
 23. Theapparatus of claim 17, wherein said end effector further comprises asecond-axis rotor connected to said tube, wherein said attachment memberconnects to said second-axis rotor to connect to said tube.
 24. A methodof inspecting a structure comprising: magnetically coupling a controlsystem to an attachment member of an end effector; coupling aninspection probe to the end effector, wherein the end effectorcomprises: a telescoping arm; a tube for receiving the telescoping arm,wherein the arm is at least partially disposed within the tube; a forcemechanism interoperably coupled to the arm and the tube for providing aforce to dynamically extend the arm from the tube; and an attachmentmember connected to the tube for magnetically attaching the end effectorto the control system by magnetic coupling and from which thetelescoping arm extends, wherein the attachment member comprises atleast one magnetic coupling mechanism selected from the group of amagnet and ferromagnetic material, and wherein the magnetic couplingmechanism is capable of cooperating with a magnetic coupling mechanismof the control system to create the magnetic coupling between the endeffector and the control system, wherein the attachment member comprisesat least one alignment member capable of proving alignment of the endeffector with respect to at least one corresponding indentation in thecontrol system for when the end effector is magnetically attached to thecontrol system, wherein the step of coupling an inspection probecomprises the step of aligning the end effector with respect to thecontrol system by disposing the at least one alignment member into theat least one corresponding indentation in the control system forproviding alignment of the end effector with respect to the at least onecorresponding indentation in the control system for when the endeffector is magnetically attached to the control system; positioning theinspection probe against a surface of the structure; and controllinginspection of the structure with the control system.
 25. The method ofclaim 24, wherein the step of positioning the inspection probe comprisesthe step of telescoping an arm of the end effector to permit theinspection probe to contact the surface of the structure.
 26. The methodof claim 25, wherein the step of telescoping an arm of the end effectorcomprises the step of exerting a force by the force mechanism of the endeffector upon the arm of the end effector, wherein the force is inclinedto extend the arm from the tube.
 27. The method of claim 24, furthercomprising the step of releasing the magnetic coupling of the controlsystem and the attachment member by separating the control system andthe attachment member.
 28. The method of claim 27, wherein said step ofreleasing the magnetic coupling comprises the step of protruding anextension from at least one of the control system and the attachmentmember between the control system and the attachment member.
 29. Themethod of claim 24, further comprising the step of separating thecontrol system and the attachment member by manipulating at least onemagnetic coupling offset release clamp, connected to at least one of thecontrol system and the attachment member, configured for protruding anextension of the at least one magnetic coupling offset release clampbetween the control system and the attachment member.
 30. The method ofclaim 24, further comprising the step of securing at least onereleasable clamp, connected to one of the attachment member and thetube, to connect the attachment member to the tube.
 31. The method ofclaim 24, further comprising the step of connecting a detachableextension tube between the tube and the attachment member, wherein thedetachable extension tube is capable of being unconnected from the tubeand the attachment member and wherein the tube and the attachment memberare capable of being connected without the detachable extension tube.32. An end effector comprising, a telescoping arm; a tube for receivingsaid telescoping arm, wherein said arm is at least partially disposedwithin said tube; a force mechanism interoperably coupled to said armand said tube for providing a force to dynamically extend said arm fromsaid tube; and an attachment member connected to said tube formagnetically attaching the end effector to another component by magneticcoupling and from which said telescoping arm extends, wherein saidattachment member comprises at least one magnetic coupling mechanismselected from the group of a magnet and ferromagnetic material, andwherein said magnetic coupling mechanism is capable of cooperating witha magnetic coupling mechanism of said another component to create themagnetic coupling between said end effector and said another component,wherein said attachment member further comprises at least one releasableclamp for connecting said attachment member to said tube.
 33. The endeffector of claim 32, wherein said releasable clamp is capable ofpermitting adjustment of the position of said tube with respect to saidattachment member by releasing said releasable clamp connecting saidattachment member to said tube.
 34. An end effector comprising, atelescoping arm; a tube for receiving said telescoping arm, wherein saidarm is at least partially disposed within said tube; a force mechanisminteroperably coupled to said arm and said tube for providing a force todynamically extend said arm from said tube; an attachment memberconnected to said tube for magnetically attaching the end effector toanother component by magnetic coupling and from which said telescopingarm extends, wherein said attachment member comprises at least onemagnetic coupling mechanism selected from the group of a magnet andferromagnetic material, and wherein said magnetic coupling mechanism iscapable of cooperating with a magnetic coupling mechanism of saidanother component to create the magnetic coupling between said endeffector and said another component, and a detachable extension tubeconnected between said tube and said attachment member, wherein saiddetachable extension tube is capable of being detached from said tubeand said attachment member and wherein said tube and said attachmentmember are capable of being connected without said detachable extensiontube.
 35. An end effector comprising, a telescoping arm; a tube forreceiving said telescoping arm, wherein said arm is at least partiallydisposed within said tube; a force mechanism interoperably coupled tosaid arm and said tube for providing a force to dynamically extend saidarm from said tube; and an attachment member connected to said tube formagnetically attaching the end effector to another component by magneticcoupling and from which said telescoping arm extends, wherein saidattachment member comprises at least one magnetic coupling mechanismselected from the group of a magnet and ferromagnetic material, andwherein said magnetic coupling mechanism is capable of cooperating witha magnetic coupling mechanism of said another component to create themagnetic coupling between said end effector and said another component,wherein said attachment member comprises at least one magnetic couplingoffset release clamp.
 36. The end effector of claim 35, wherein saidmagnetic coupling offset release clamp comprises at least one extension,wherein said extension is adapted to adjustably protrude from saidattachment member.